The difference between Administrator and Controller

When used as nouns, administrator means one who administers affairs, whereas controller means one who controls something.

check bellow for the other definitions of Administrator and Controller

Administrator as a noun:

One who administers affairs; one who directs, manages, executes, or dispenses, whether in civil, judicial, political, or ecclesiastical affairs; a manager
Administrator as a noun (legal):

A person who manages or settles the estate of an intestate, or of a testator when there is no competent executor; one to whom the right of administration has been committed by competent authority
Administrator as a noun (computing):

One who is responsible for software installation, management, information and maintenance of a computer or network

Controller as a noun:

One who controls something.
Controller as a noun (electronics):

Any electric or mechanical device for controlling a circuit or system.
Controller as a noun (business):

A person who audits, and manages the financial affairs of a company or government; a comptroller.
Controller as a noun (computing):

A mechanism that controls or regulates the operation of a machine, especially a peripheral device in a computer.
Controller as a noun (nautical):

An iron block, usually bolted to a ship's deck, for controlling the running out of a chain cable. The links of the cable tend to drop into hollows in the block, and thus hold fast until disengaged.
Controller as a noun (espionage):

The person who supervises and handles communication with an agent in the field.
Controller as a noun (linguistics):

The subject of a control verb. See
Controller as a noun (software architecture):

In software applications using the model-view-controller design pattern, the part or parts of the application that treat input and output, forming an interface between models and views.